Stop Lamp Relay Circuit Short
Table of contents
B3903 SATURN Possible Causes
- Faulty Stop Lamp Relay
- Stop Lamp Relay harness is open or shorted
- Stop Lamp Relay circuit poor electrical connection
- Faulty Body Control Module (BCM)
How do I fix code B3903 SATURN?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Tech Notes
- B3903 02 Stop Lamp Relay Circuit Short to Ground
- B3903 05 Stop Lamp Relay Circuit Short to Battery or Open
Cost of diagnosing the B3903 SATURN code
The cost of diagnosing the B3903 SATURN code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
B3903 SATURN Description
The Body Control Module (BCM) supplies voltage to the Center High Mount Stop Lamp (CHMSL) and the Powertrain Control Module (PCM) when the stop lamps are active. The Diagnostic Trouble Code (DTC) sets when if the stop lamp switch signal circuit is shorted to ground for 125 ms or if is open or shorted to voltage for 125 ms.